Mattia Binotto thinks Ferrari's rivals complained about the legality of the Italian team's 2019 engine to "put pressure on us".
Some rival teams claimed the Maranello-made power unit suddenly became 50 horsepower better in 2019, prompting a late-season round of scrutiny by the FIA that is ongoing.
"The truth is far from that number," team boss Binotto told Auto Motor und Sport.
"We assume a maximum of 20hp, which is still respectable and a big advantage that we are proud about."
In contrast, he said Mercedes' advantage in 2014 was more like 80hp and up.
Binotto explained that he doesn't even think Ferrari's rivals actually doubt the legality of the engine.
"They're probably using it to put pressure on us, because pressure distracts. It's part of the game in Formula 1 to unsettle your opponent," he said.
However, those same rivals also point out that Ferrari's straightline speed suddenly vanished when the FIA started issuing technical directives on the matter.
"That's right, but they're drawing the wrong conclusions," Binotto insisted.
"We did not change the operating conditions of the engines. To generate more downforce, we increased the drag, making us a bit faster in the corners and slower on the straights."
He also expects the FIA to continue to clamp down on interpretations of the engine rules.
"We are satisfied with that, because it gives more clarity in a very complex set of rules," said the Italian.
"Will they be completely clear? Probably not. I am sure there are a few more directives to come, but as a team we support the FIA in eliminating ambiguity in the rules."
